Clean the carbon pads by rubbing GENTLY with a Q-tip soaked in IPA. A little carbon rubbed off is okay (enough to see a shadowy smear); if you rub off enough to turn the Q-tip black, too hard or try a different solvent.
Yea ... I've cleaned the contacts and carbon "pills" very well when I got the scope several years ago. I'm going to clean again but how are they getting dirty? I don't think it's an issue with cleaning.
Ah, the NASA "space pen" answer. An alternative is to go all Russian and use a pencil. In this case, a nice soft pencil and just touch up the surface of the pads by giving them a good scribbling. Just blow off any loose graphite after you're finished. It may not be clever, it may not be pretty, but it's worked for me in the past. I have very soft artist's graphite 'crayons' handy (no wood, just a very thick 'lead' with a paper wrapper) so I can't offer too much useful guidance on what grade of pencil to use, but I reckon that a 4B would be a fair starting point.
Very interesting solution. I'm putting that as a probable thing to try after I investigate something ...
When I had to repair these carbon buttons I used in the past some gold foil. Worked nicely but a little bit tricky to handle. Don't! Breathe!
Again interesting idea, may try that.
I just took some old remote control and used a blade to remove the carbon pad from a rarely used button. I then removed the non-working carbon pad and glued the "new" one on.
Yes replacing the pads is another thing that people do and no doubt it works.
But ... I'm going to do an investigation for a little while and keep this on the bench. The PCB that the keys are pressing against is pristine and as clean as can be, so we know it's the carbon pill pads. But what I want to look at involves a microscope. There is something interesting when I use a magnifying glass ... If I find anything interesting I will post pics.
Thanks.